1. Field of the Invention
This invention relates to a waterproof connector having a pair of male and female housings inserted from the front and the rear of an attachment panel, the housings being connected by a bolt and the front housing being covered with a grommet to make the housing waterproof.
2. Description of the Related Art
Hitherto, for example, a door panel of an automobile (attachment panel) has been provided with a waterproof connector for electrically connecting various switches provided on the door panel and a power supply, drive devices, etc., on the body of the automobile.
A waterproof connector as shown in FIGS. 10-12 is known as a waterproof connector mounted on such an automobile door panel (see Japanese Utility Model Laid-Open No. Hei 7-32873).
In FIGS. 10 and 11, a waterproof connector 2 mounted on an attachment panel 1 comprises a male housing 3 inserted from the rear of the attachment panel 1, a female housing 4 inserted from the front of the attachment panel 1, a grommet 5 covering the female housing 4, a bolt 6 being inserted from the grommet 5 side for connecting the male and female housings 3 and 4, and a grommet cover 7 covering the peripheral end face of the grommet 5 as shown in FIG. 12.
A panel engagement protrusion 3a is formed on one side of the male housing 3 positioned in the upper part of the car body and is engaged with a panel holder 8 disposed on one side positioned in the lower part of the car body in a state in which they penetrate the attachment panel 1, whereby the male housing 3 is temporarily held on the attachment panel 1. The male housing 3 contains a washer 9 engaging an annular groove 6a made in the stem of the bolt 6 for preventing the bolt 6 from being removed. As shown in FIG. 13, the type wherein a plate 10 is inserted into the male housing 3 in place of the washer 9 is also available (see Japanese Utility Model Laid-Open No. Hei 5-41078).
The female housing 4 is inserted through an opening 3b of the male housing 3 and the housings 4 and 3 are connected by fastening the bolt 6 penetrating a bolt penetration tube 4a fitted into the female housing 4.
The grommet 5 comprises a derivation part 5a covering the end face to the peripheral surface of the female housing 4 positioned on the front of the attachment panel 1 and a tubular part 5b communicating with the derivation part 5a for guiding a harness (not shown), the derivation part 5a and the tubular part 5b being molded in one piece made of synthetic rubber, etc.
An open end of the derivation part 5a comes in elastic contact with the attachment panel 1 by fastening the bolt 6, whereby a seal property to the inside of the connector is provided. The cover part 5a has a lip part 5c sandwiched between parts of the male and female housings 3 and 4 positioned in the upper part of the car body from the axial direction of the bolt 6, thereby preventing water drops traveling on the attachment panel 1 from entering the derivation part 5a.
The grommet cover 7 comprises a plurality of holes 7a engaging a plurality of protrusions 5d projected from the outer peripheral surface of the grommet 5. The holes 7a are engaged with the protrusions 5d so as to cover the outer peripheral surface of the grommet 5, whereby the grommet cover 7 is held on the grommet 5 and at the same time, fastens the grommet 5 from the outside, thereby providing hermeticity to the female housing 4 by the grommet 5 and preventing the grommet 5 from falling out from the female housing 4.
In the structure, a plurality of terminals (not shown) are inserted into the male housing 3, then the attachment panel 1 is temporarily held on the male housing 3, the female housing 4 is covered with the grommet 5, and the grommet 5 is covered with the grommet cover 7, then the unit is engaged with the male housing 3 for engaging the female housing 4. The bolt 6 is inserted through a bolt insertion tubular part 5e of the grommet 5 and is threadably engaged with a female screw member 11 disposed in the male housing 3, whereby the male and female housings 3 and 4 are coupled.
In the waterproof connector 2 of the structure as described above, the grommet 5 is covered with one grommet cover 7 and moreover fastening the grommet 5 depends only on the mold shape of both the grommet 5 and the grommet cover 7. Thus, the grommet cover 7 having an inner form smaller than the outer form of the grommet 5 must be mounted.
Therefore, the fastening accuracy does not become stable due to a mold error of the grommet 5 and the grommet cover 7; in addition, it is difficult and intricate to attach and detach the grommet cover 7 to and from the grommet 5.
In the waterproof connector 2 of the structure as described above uses a washer 9 for preventing the bolt 6 from being removed. Thus, if the bolt 6 is broken or parts are replaced accompanying an energization failure, it is hard to separate the bolt 6 from the washer 9.
Then, the plate 10 can be used in place of the washer 9. However, since the plate 10 is simply inserted into the male housing 3 (or the female housing 4), a problem occurs in plate 10 may be easily removed while the waterproof connector 2 is assembled or when the vehicle runs. In addition, a reasonable depth is required to prevent the plate 10 from being removed, causing a new problem of an increases in material costs to arise.
In the grommet cover 7 of the waterproof connector 2 of the structure as described above is the surface of the grommet 5 and the peripheral surface orthogonal to the surface (the face where a plurality of protrusions 5d are formed). Thus, for example, when the bolt 6 does not exist or is broken, if the pipe part 5b of the grommet 5 is extended unexpectedly, a part of the introduction part 5a of the grommet 5 peels off from the female housing 4 or the introduction part 5a is removed completely.
In the waterproof connector 2 of the structure as described above, when the bolt 6 is inserted in the bolt insertion tubular part 5e, the bolt insertion tubular part 5e is dragged in the insertion direction of the bolt insertion tubular part 5e due to load in the insertion direction and a clearance easily occurs between the bolt 6 and the bolt insertion tubular part 5e. If the bolt 6 is rotated to couple the female and male housings 3 and 4, the bolt insertion tubular part 5e is twisted due to load in the rotation direction and a clearance easily occurs between the bolt 6 and the bolt insertion tubular part 5e.
In the waterproof connector 2 of the structure as described above, it is feared that water drops traveling on the surface of the attachment panel 2 may pass through the space between the attachment panel 2 and the grommet 5 and enter the derivation part 5a from between the panel engagement protrusion 3a and the lip part 5c.